This study shows that aerobic fitness (i.e. the maximal amount of oxygen a person is able to use during physical activity) is severely reduced in persons with multiple sclerosis (MS) relative to healthy people of the same age and gender. Furthermore, persons with MS who were less fit experienced more limitations in physical functioning, and restrictions in participation and autonomy indoors and outdoors, as well as in social life and relationships.

Methods: Aerobic capacity was measured with a leg ergometer and was expressed as maximal oxygen uptake (VO2max, in ml/kg/min). Physical activity was measured with the Physical Activity Scale for Individuals with Physical Disabilities (PASIPD), physical functioning with the Short Form 36 – physical functioning (SF36-pf), and participation and autonomy in daily living with the Impact on Participation and Autonomy questionnaire (IPA). Multiple regression analyses were performed, adjusted for potential confounders (gender, age, body mass index, educational level, and employment status).

Conclusion: Maximum aerobic capacity was severely reduced in persons with multiple sclerosis-related fatigue. This partly explains the limited physical functioning and restrictions in participation and autonomy indoors, outdoors and in social life and relationships in these persons.